oh-ho-ho! it's pur-rity! alas, it's not mine. it's not nutes, it's not sunburn. it's in a private area of a nursery, being propagated... hence prolly rare or being hybridized or smth like that. it's in miami, fl. it's not for sale. i asked for permission to view private greenhouses and took some pics... lotsa pretties there... this particular very intriguing. but couldn't really ask what it was! it def looks like largish xanadu.
i looked at filippino site - can't see anything close though. red usually comes from ph. erubescence. never seen any hybrids with red margins like that!
mjsponies, go ahead, please post on facebook (i am not on it and don't plan to be either ;).
fern is not asplenium - will tell you in a coupla days - am not near my plantfiles at the moment. it's a beauty and i know it's name :))).

yep, ph. mayoi seems just like what it is! but i can't believe it would be nutes; these guys are pro's - they sell and propagate lots of fantastic aroids and rather hard to find variegated philos and monsteras and lots more. though their labeling is rather poor, even for sales stuff. last year was an exceptionally warm winter - only a few nights around 56F, most days in hi 70s and low 80s. so temps would not be problematic. and by the way - what kind of nutes can produce such a well defined red margin? this plant and all of the rest is in covered greenhouses.
after i looked at asplenium ferns i see why you thought it was an asplenium. though it has long thin petioles, but the other aspleniums all seem to have fronds that start at the base. some of the frilly aspleniums look quite close. one more day and you'll know.

i got the fern name - can't find any pics of it on-line, but here it is: polypodium polycarpon 'filigree'. it's fantastic looking too. both of these plants are in private 'hybridization/propagation' section. this are plants in development so to speak, not for sale. there was nobody to ask, the place is huge. perhaps, i'll be more persevering next time. and if it was that easy to turn philo red - why wouldn't everybody do it? i don't think it's that simple of an answer. and it was the only plant of this kind. so i am reluctant to name a nursery. if i see it again, i'll take more and better pics and perhaps find smbody to talk too.
have you heard of this cultivar of fern before?

ok, i finally visited the nursery again. it is Palm Hammock Orchid estate in Miami, FL. i just love the place. this time instead of one plant there was a whole shelf of them in 'private propagation section'. and they WERE marked Ph. mayoii. and from what i could observe - the red appears strictly on older leaves - as they age they get red on the edges, but a few leaves were totally burgundy red - very pretty.

skylark said:...marked Ph. mayoii. and from what i could observe - the red appears strictly on older leaves - as they age they get red on the edges, but a few leaves were totally burgundy red - very pretty.

well, this year i did not have enough time to go thru the back room (it took close to 2 hours last time! what with all the picture taking...).
and i just found out that PHOE has sold their plot in South Miami and moved the shop to Redlands . Of course, i'll visit them there too...but! i don't know if they will have a back room there...Tim Anderson is a very well known hybridizer of begonias, so it's a famous place

so, in short - that plant , actually several (there was a whole table of them - confirmed fro a pic), was there in the back room for sev years.
but i have not seen it on their shelves for sale. It was a pretty chaotic place - like a Sleeping kingdom, just fascinating to visit!
a knockout in my book !